Polyolefin-based hot melt adhesive composition

ABSTRACT

A polyolefin-based hot melt adhesive composition made from or containing:(A) 28-75 wt. % of a copolymer of butene-1 with Melt Flow Rate values, measured according to ISO 1133 (190° C., 2.16 kg), from 200 to 1500 g/10 min.; and(B) 25-72 wt. % of at least one additional component selected from the group consisting of waxes, resins, plasticizers, additional polymers and mixtures thereof,wherein the amounts of A) and B) are referred to the total weight of A)+B).

FIELD OF THE INVENTION

In general, the present disclosure relates to the field of chemistry.More specifically, the present disclosure relates to polymer chemistry.In particular, the present disclosure relates to a polyolefin-based hotmelt adhesive composition.

BACKGROUND OF THE INVENTION

In some instances, hot melt adhesive compositions are made from orcontaining butene-1 homo- or copolymers.

In some instances, the polybutene-1 used in the hot melt adhesivescompositions are visbroken with peroxides to achieve low viscosityvalues. In some instances, peroxidic degradation causes unpleasant odorand high yellow index and prevents use of the composition in sometechnical fields, such as food packaging.

In some instances, ex-reactor low molecular weight polyolefins used inhot melt adhesive compositions.

SUMMARY OF THE INVENTION

In a general embodiment, the present disclosure provides a hot meltadhesive composition made from or containing:

(A) 28-75 wt. % of a copolymer of butene-1 with at least one comonomerselected from the group consisting of ethylene, propylene, C5-C10alpha-olefins and mixtures thereof, having copolymerized comonomercontent of 0.5-5.0 wt. % and Melt Flow Rate (MFR) values measuredaccording to ISO 1133 (190° C., 2.16 kg) from 200 to 1,500 g/10 min.;and(B) 25-72 wt. % of at least one additional component selected from thegroup consisting of waxes, resins, plasticizers, additional polymers andmixtures thereof, wherein the amounts of A) and B) are referred to thetotal weight of A)+B).

BRIEF DESCRIPTION OF THE DRAWINGS

The claimed subject matter may be understood by reference to thefollowing description taken in conjunction with the accompanying figuresin which:

FIG. 1 provides line graphs showing the viscosity values at differenttemperatures of the hot melt adhesive composition of Examples 3 and 4 incomparison with the viscosity values recorded under the same conditionfor the hot melt adhesive composition of Comparative Examples 5 and 6;

FIG. 2 provides line graphs showing the viscosity values at differenttemperatures of the hot melt adhesive composition of Examples 7 and 8 incomparison with the viscosity values recorded under the same conditionfor the hot melt adhesive composition of Comparative Examples 9 and 10;

FIG. 3 provides bar graphs showing the Overlap Shear Strength values ofthe hot melt adhesive compositions of Examples 7-8 and ComparativeExamples 9 and 10 on different substrates.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “room temperature” refers to a temperature of25±2° C. measured at 50% of relative humidity.

As used herein, the term “solid” refers to a material having a definitevolume and shape at room temperature.

As used herein, the expression “not solid” refers to a matter which is“rheologically liquid”, that is, a matter having a Viscous Modulus G″greater than the matter's Elastic Modulus G′, or also, what isequivalent by definition, a Tan Delta greater than 1, wherein the valuesbeing measured at room temperature. As used herein, the expressionencompasses matter that, even if the matter can be shaped in a certainshape, the matter (in a period of time not longer than one day)permanently deforms and spontaneously flows, even by the action of thematter's own weight, taking the shape of the container that contains thematter or of the solid surface on which the matter is lying. As usedherein, the expression includes materials described as “liquid” as wellas materials defined as “creamy”, “pasty”, “jelly-like”, “fluid”,“greasy”, “semi-solid”, and the like.

In a general embodiment, the present disclosure provides a hot meltadhesive composition made from or containing:

(A) 28-75 wt. % of a copolymer of butene-1 with at least one comonomerselected from the group consisting of ethylene, propylene, C5-C10alpha-olefins and mixtures thereof, having (total) copolymerizedcomonomer content of 0.5-5.0 wt. % and Melt Flow Rate (MFR) valuesmeasured according to ISO 1133 (190° C., 2.16 kg) from 200 to 1500 g/10min.; and(B) 25-72 wt. % of at least one additional component selected from thegroup consisting of waxes, resins, plasticizers, additional polymers andmixtures thereof, wherein the amounts of A) and B) are referred to thetotal weight of A)+B).

In some embodiments, the butene-1 copolymer component (A) has a MFRmeasured according to ISO 1133 (190° C., 2.16 kg) from 200 to less than1500 g/10 min., alternatively from 400 to less than 1500 g/10 min.,alternatively from 500 to 1300 g/10 min.

In some embodiments, the at least one comonomer is selected from thegroup consisting of ethylene, propylene, C5-C10 alpha-olefins andmixtures thereof, alternatively from the group consisting of ethylene,propylene, hexene-1, octene-1 and mixture thereof.

In some embodiments, the at least one comonomer is ethylene.

In some embodiments, the butene-1 copolymer component (A) has acopolymerized comonomer content, of 0.5-3.0 wt. %, alternatively from0.7 to less than 2.0 wt. %, alternatively of 0.7-1.5 wt. %. In someembodiments, the butene-1 copolymer component (A) has a copolymerizedethylene content of 0.5-3.0 wt. %, alternatively from 0.7 to less than2.0 wt. %, alternatively of 0.7-1.5 wt. %.

In some embodiments, the butene-1 component (A) is made from orcontaining a butene-1 copolymer composition made from or containing:

(A1) a butene-1 homopolymer or a copolymer of butene-1 with at least onecomonomer selected from the group consisting of ethylene, propylene,C5-C10 alpha-olefins and mixtures thereof, having a copolymerizedcomonomer content (C_(A1)) of up to 3 wt. %;(A2) a copolymer of butene-1 with at least one comonomer selected fromthe group consisting of ethylene, propylene, C5-C10 alpha-olefins andmixtures thereof, having a copolymerized comonomer content (C_(A2)) of3-10 wt. %;wherein the butene-1 copolymer composition having a total copolymerizedcomonomer content of 0.5-5.0 wt. % referred to the sum of (A1)+(A2). Insome embodiments, the butene-1 copolymer composition has a content offraction soluble in xylene at 0° C. equal to or less than 60 wt. %,determined on the total weight of (A1)+(A2).

In some embodiments, the relative amount of component (A1) and (A2)ranges from 10% to 40% by weight, alternatively from 15% to 35% byweight, of (A1) and from 90% to 60% by weight, alternatively from 85% to65% by weight, of (A2), wherein the amounts being referred to the sum of(A1)+(A2).

In some embodiments, the butene-1 copolymer composition is as describedin Patent Cooperation Treaty Publication No. WO2018/007280, which isherein incorporated by reference.

In some embodiments, the butene-1 copolymer component (A) has at leastone of the following additional features:

(a) a molecular weight distribution (Mw/Mn) lower than 4, alternativelylower than 3; alternatively lower than 2.5, the lower limit being 1.5 inthe cases; and/or(b) a melting point (TmII) lower than 110° C., alternatively lower than100° C., alternatively lower than 90° C.; and/or(c) a melting point (TmII) higher than 80° C.; and/or(d) a glass transition temperature (Tg) in the range from −40° C. to−10° C., alternatively from −30° C. to −10° C.; and/or(e) a rotational (Brookfield) viscosity at 180° C. (shear rate 100 s−1)of from 5,000 to 50,000 mPa·sec, alternatively from 8,000 to 20,000mPa·sec; and/or(f) an X-ray crystallinity in the range 25-60%.

In some embodiments, the butene-1 copolymer (A) has the additionalfeatures (a)-(f).

In some embodiments, the butene-1 copolymer component (A) has at leastone of the further following additional features:

(i) an intrinsic viscosity (IV) measured in tetrahydronaphthalene (THN)at 135° C. equal to or lower than 0.8 dl/g, alternatively between 0.2and 0.6 dl/g; and/or(ii) a density of higher than 0.885-0.925 g/cm³, alternatively of0.890-0.920 g/cm³; and/or(iii) a yellowness index of less than 0; alternatively ranging from −1to −5.

In some embodiments, the butene-1 copolymer (A) has the additionalfeatures (i)-(iii).

In some embodiments, the butene-1 copolymer (A) has the additionalfeatures (a)-(f) and the additional features from (i) to (iii).

In some embodiments, the butene-1 copolymer component (A) is obtained bycopolymerizing butene-1 and the at least one comonomer in the presenceof a catalyst system obtainable by contacting:

a stereorigid metallocene compound;an alumoxane or a compound capable of forming an alkyl metallocenecation; and, optionally,an organo aluminum compound.

Patent Cooperation Treaty Publication Nos. WO2004/099269, WO2006/045687and WO2018/007280 are herein incorporated by reference. In someembodiments, the publications describe a process and a catalysts systemfor producing the butene-1 copolymer component (A).

In some embodiments, the butene-1 copolymer component (A) is obtained bya polymerization process carried out in one or more reactors connectedin series. In some embodiments, the polymerization process is carriedout in reactors connected in series and the catalyst is added in thefirst reactor, alternatively in more than one reactor. In someembodiments, the polymerization process is carried out in the liquidphase, optionally in the presence of an inert hydrocarbon solvent, or inthe gas phase, using fluidized bed or mechanically agitated gas phasereactors. In some embodiments, the polymerization process is carried outby using liquid butene-1 as polymerization medium. In some embodiments,the polymerization temperature ranges from 20° C. to 150° C.,alternatively from 50° C. to 90° C., alternatively from 65° C. to 82° C.

In some embodiments, hydrogen is used to regulate the molecular weightof butene-1 copolymers. In some embodiments, the concentration ofhydrogen during the polymerization reaction carried out in the liquidphase is higher than 1800 molar ppm and lower than 6000 molar ppm,alternatively ranges from 2000 molar ppm to 6000 molar ppm.

In some embodiments, butene-1 copolymers having low melting point areobtained by selecting the copolymerized comonomer content. In someembodiments, butene-1 copolymers having low melting point are obtainedby selecting the copolymerized ethylene content. In some embodiments,the butene-1 copolymer component (A) is obtained with a polymerizationprocess wherein the (total) amount of the comonomer in the liquid phaseranges from 0.1 wt. % to 8 wt. %, alternatively from 0.2 wt. % to 6 wt.%, with respect to the total weight of butene-1 monomer present in thepolymerization reactor. In some embodiments, the comonomer is ethylene.

In some embodiments, the butene-1 copolymer (A) is a butene-1 copolymercomposition made from or containing components (A1) and (A2) and thepolymerization process includes at least two polymerization stages,carried out in two or more reactors connected in series. In someembodiments, component (A1) is a copolymer and, for the preparation ofcomponent (A1), the amount of comonomer in the liquid phase is from 0.1wt. % to 1.2 wt. %. In some embodiments, the amount of comonomer in theliquid phase is from 1 wt. % to 8 wt. % for the preparation of component(A2).

The hot melt adhesive composition is further made from or containing atleast one additional component (B) selected from the group consisting ofwaxes (1), resins (2), plasticizers (3), additional polymers (4) andmixtures thereof.

In some embodiments, the at least one additional component (B) is solidat room temperature.

In some embodiments, the additional component (B) is not a “not solid”viscosity modifier.

In some embodiments, the at least one additional component (B) isselected from the group consisting of waxes (1), resins (2), additionalpolymers (4) and mixtures thereof. In some embodiments, the at least oneadditional component (B) is selected from the group consisting of waxes(1), resins (2) and mixtures thereof.

In some embodiments, waxes (1) are selected from the group consisting ofpolyolefin waxes; natural (plant, animal or mineral) waxes; petroleumwaxes; synthetic waxes made by polymerizing CO and Hz; naphthalenicwaxes and mixtures thereof. In some embodiments, the petroleum waxes areparaffin waxes. In some embodiments, the synthetic waxes made bypolymerizing CO and H2 are Fischer-Tropsch waxes. In some embodiments,waxes (1) are Fischer-Tropsch waxes.

In some embodiments, resins (2) used as component (B) are tackifiersthat selected from the group consisting of hydrogenated hydrocarbonresins and derivatives thereof; terpene-derived resins; natural resinsand natural resin esters; and mixtures thereof. In some embodiments, thehydrogenated hydrocarbon resins and derivatives thereof are selectedfrom the group consisting of aliphatic hydrocarbon resins, aromatichydrocarbon resins and aliphatic/aromatic hydrocarbon resins. In someembodiments, the terpene-derived resins are selected from the groupconsisting of polyterpenes and terpene/phenolic resins. In someembodiments, the natural resins and natural resin esters are selectedfrom the group consisting of rosin, rosin ester and tall oil rosinester. In some embodiments, resins (2) are hydrogenated hydrocarbonresins.

In some embodiments, the resin (2) has a ring and ball softening pointof higher than 120° C., alternatively equal to or higher than 125° C.,measured according to ASTM Standard E 28.

In some embodiments, plasticizers (3) are selected from the groupconsisting of plasticizing oils; olefin oligomers or low molecularweight polyolefins; and mixtures thereof. In some embodiments, theplasticizing oils are mineral oils. In some embodiments, the olefinoligomers or low molecular weight polyolefins are liquid polybutylenes.

In some embodiments, the at least one further component (B) is anadditional polymer (4) different from the butene-1 copolymer (A) andselected from the group consisting of amorphous poly-alpha-olefins,thermoplastic polyurethanes, ethylene/(meth)acrylate copolymers,ethylene/vinyl acetate copolymers, and mixtures thereof.

In some embodiments, the viscosity and adhesion properties of the hotmelt adhesive composition are tailored. In some embodiments, the presentdisclosure provides a process for preparing an article of manufactureincluding the step of applying a hot melt adhesive composition to asubstrate and an additional step selected from the group consisting ofwoodworking, packaging and assembling. In some embodiments, the hot meltadhesive composition is applied to a substrate and then used inwoodworking, for packaging, in the general assembly field. In someembodiments, the hot melt adhesive composition is used to assemblecomponents of electrical equipment, ceramics, furniture, textiles,upholstery, leather, plastic, paper and cardboard.

In some embodiments, the hot melt adhesive composition is made from orcontaining a composition (i) made from or containing:

(A) 30-40 wt. % of a copolymer of butene-1;(B.1) 15-25 w. % of at least one wax,(B.2) 42-52 wt. % of at least one resin; and wherein the amounts of (A),(B.1) and (B.2) are referred to the total weight of (A)+(B.1)+(B.2).

In some embodiments, composition (i) is used in the packaging field toassemble paper, cardboard and the like.

In some embodiments, the hot melt adhesive composition made from orcontaining composition (i) has a rotational (Brookfield) viscosity at180° C. (shear rate 100 s−1) of lower than 7,000 mPa·s, alternativelyequal to or lower than 5,000 mPa·s, alternatively equal to or lower than3,000 mPa·s., the lower limit being 1,000 mPa·s in the cases.

In some embodiments, the Brookfield viscosity at 170° C. (shear rate 100s−1) is from 4,000 mPa·s. to 1,500 mPa·s.

In some embodiments, the hot melt adhesive composition is made from orcontaining a composition (ii) made from or containing:

(A) 65-75 wt. % of a copolymer of butene-1; and(B.2) 25-35 wt. % of at least one resin, wherein the amounts of (A) and(B.2) are referred to the total weight of (A)+(B.2).

In some embodiments, the hot melt adhesive composition made from orcontaining composition (ii) has a rotational (Brookfield) viscosity at180° C. (shear rate 100 s−1) of 5,000-25,000 mPa·s, alternatively of7,000-25,000 mPa·s, alternatively of 7,000-20,000 mPa·s, alternativelyof 10,000-20,000 mPa·s.

In some embodiments, the Brookfield viscosity at 170° C. (shear rate 100s−1) is equal to or higher than 7,000 mPa·s, alternatively equal to orhigher than 10,000 mPa·s, the upper limit being 30,000 mPa·s in thecases.

In some embodiments, the resin (B.2) has a ring and ball softening pointof higher than 120° C., alternatively equal to or higher than 125° C.,measured according to ASTM Standard E 28.

In some embodiments, the hot melt adhesive composition made from orcontaining composition (ii) has at least one of the followingproperties:

an Overlap Shear Strength (OLS) value on at least one material selectedthe group consisting of polypropylene, aluminum alloy and wood equal toor higher than 2 MPa, alternatively higher than 3 MPa. In someembodiments, the hot melt adhesive composition made from or containingcomposition (ii) has an OLS value equal to or higher than 2 MPa on thematerials; and/oropen time higher than 250 seconds, alternatively higher than 270seconds.

In some embodiments, the hot melt adhesive composition made from orcontaining composition (ii) has an OLS value equal to or higher than 2MPa on the materials and an open time value higher than 250 seconds,alternatively higher than 270 seconds.

In some embodiments, the hot melt adhesive composition made from orcontaining composition (ii) is used in woodworking and in the generalassembly field. In some embodiments, the hot melt adhesive compositionmade from or containing composition (ii) is used to assemble componentsof electrical equipment, ceramics, furniture, textiles, upholstery,leather, plastic, etc.

In some embodiments, the hot melt adhesive composition shows thermalstability and reduced color change.

In some embodiments, the hot melt adhesive composition are further madefrom or containing additives selected from the group consisting ofantioxidants, UV stabilizers, aging protection agents, nucleating agentsand mixtures thereof. In some embodiments, nucleating agents areselected from the group consisting of isotactic polypropylene,polyethylene, amides and talc. In some embodiments, the total amount ofthe additives is from 0.01 to 1 wt. %, with respect to the total weightof the hot melt adhesive composition.

In some embodiments, the hot melt adhesive composition is prepared byblending of the components in the molten state in a single- or twinscrew extruder.

The following examples are illustrative only, and are not intended tolimit the scope of the invention in any manner whatsoever.

EXAMPLES

The following analytical methods are used to determine the propertiesreported in the description and in the examples.

Melt flow rate (MFR) was measured according to ISO 1133 (190° C., 2.16kg, except where different load and temperatures are specified).

Comonomer content (wt. %) measured via IR spectroscopy.

The spectrum of a pressed film of the polymer was recorded in absorbancevs. wavenumbers (cm⁻¹). The following measurements were used tocalculate the ethylene content: a) area (At) of the combinationabsorption bands between 4482 and 3950 cm⁻¹ which was used forspectrometric normalization of film thickness;

b) factor of subtraction (FCR_(c2)) of the digital subtraction betweenthe spectrum of the polymer sample and the absorption band due to thesequences BEE and BEB (B: 1-butene units, E: ethylene units) of themethylenic groups (CH₂ rocking vibration);c) Area (A_(c2,block)) of the residual band after subtraction of theC₂PB spectrum and came from the sequences EEE of the methylenic groups(CH₂ rocking vibration).

Apparatus

A Fourier Transform Infrared spectrometer (FTIR) was used. A hydraulicpress with platens heatable to 200° C. (Carver or equivalent) was used.

Method

Calibration of (BEB+BEE) Sequences A calibration straight line wasobtained by plotting % (BEB+BEE)wt vs. FCR_(c2)/A_(t). The slope Gr andthe intercept Lr were calculated from a linear regression.

Calibration of EEE Sequences

A calibration straight line was obtained by plotting % (EEE)wt vs.A_(c2,block)/A_(t). The slope G_(H) and the intercept I_(H) werecalculated from a linear regression.

Sample Preparation

Using a hydraulic press, a thick sheet was obtained by pressing about1.5 g of sample between two aluminum foils. If homogeneity was inquestion, a minimum of two pressing operations occurred. A small portionwas cut from the resulting sheet to mold a film. The film thicknessranged between 0.1-0.3 mm. The pressing temperature was 140±10° C. TheIR spectrum of the sample film was collected as soon as the sample wasmolded.

Procedure

The instrument data acquisition parameters were as follows:

Purge time: 30 seconds minimum.

Collect time: 3 minutes minimum.

Apodization: Happ-Genzel.

Resolution: 2 cm⁻¹.

Collect the IR spectrum of the sample vs. an air background.

Calculation

Calculate the concentration by weight of the BEE+BEB sequences ofethylene units:

${\%\mspace{14mu}\left( {{BEE} + {BEB}} \right)\mspace{14mu}{wt}} = {{{Gr}\frac{FCR_{C2}}{A_{t}}} + I_{r}}$

Calculate the residual area (AC2,block) after the subtraction, using abaseline between the shoulders of the residual band.

Calculate the concentration by weight of the EEE sequences of ethyleneunits:

${\%\mspace{14mu}\left( {E{EE}} \right)\mspace{14mu}{wt}} = {{G_{H}\frac{A_{{C\; 2}\;,{block}}}{A_{t}}} + I_{H}}$

Calculate the total amount of ethylene percent by weight:

% C2wt=[%(BEE+BEB)wt+%(EEE)wt]

Mw/Mn determination. Measured by way of Gel Permeation Chromatography(GPC) in 1,2,4-trichlorobenzene (TCB). Molecular weight parameters (Mn,Mw, Mz) and molecular weight distributions Mw/Mn for the samples weremeasured by using a GPC-IR apparatus by PolymerChar, which was equippedwith a column set of four PLgel Olexis mixed-bed (Polymer Laboratories)and an IRS infrared detector (PolymerChar). The dimensions of thecolumns were 300×7.5 mm and their particle size was 13 μm. The mobilephase flow rate was kept at 1.0 mL/min. The measurements were carriedout at 150° C. Solution concentrations were 2.0 mg/mL (at 150° C.) and0.3 g/L of 2,6-diter-butyl-p-cresole were added to prevent degradation.For GPC calculation, a calibration curve was obtained using 12polystyrene (PS) samples supplied by PolymerChar (peak molecular weightsranging from 266 to 1220000). A third-order polynomial fit was used tointerpolate the experimental data and obtain the calibration curve. Dataacquisition and processing was done by using Empower 3 (Waters). TheMark-Houwink relationship was used to determine the molecular weightdistribution and the relevant average molecular weights: the K valueswere KPS=1.21×10⁻⁴ dL/g and KPB=1.78×10⁻⁴ dL/g for PS and polybutene(PB) respectively, while the Mark-Houwink exponents α=0.706 for PS andα=0.725 for PB were used.

For butene/ethylene copolymers, the composition was assumed constant inthe whole range of molecular weight and the K value of the Mark-Houwinkrelationship was calculated using a linear combination as reportedbelow: K_(EB)=x_(E)K_(PE) X_(B)K_(PB) where K_(EB) was the constant ofthe copolymer, K_(PE) (4.06×10⁻⁴, dL/g) and K_(PB) (1.78×10⁻⁴ dL/g) werethe constants of polyethylene (PE) and PB, x_(E) and x_(B) were theethylene and the butene weight relative amount with x_(E)+x_(B)=1. TheMark-Houwink exponents α=0.725 was used for the butene/ethylenecopolymers independently. End processing data treatment was fixed forthe samples to include fractions up at 1000 in terms of molecular weightequivalent. Fractions below 1000 were investigated via GC.

The thermal properties were determined by Differential Scanningcalorimetry (D.S.C.) on a Perkin Elmer DSC-7 instrument. The meltingtemperatures of butene-1 copolymers and of the hot melt adhesivecompositions were determined according to the following method:

TmII (melting temperature(s) measured in second heating run): a weighedsample (5-10 mg) obtained from the polymerization (or a weighed sampleof the hot melt adhesive composition) was sealed into aluminium pans andheated at 200° C. with a scanning speed corresponding to 10° C./minute.The sample was kept at 200° C. for 5 minutes, thereby allowing completemelting of the crystallites and cancelling the thermal history of thesample. Successively, after cooling to −20° C. with a scanning speedcorresponding to 10° C./minute, the peak temperature was taken ascrystallization temperature (Tc). After standing 5 minutes at −20° C.,the sample was heated for the second time at 200° C. with a scanningspeed corresponding to 10° C./min. In this second heating run, the peaktemperature(s) measured were marked as (TmII) and the area under thepeak (or peaks) as global melting enthalpy (DH TmII).The melting enthalpy and the melting temperature were measured alsoafter aging (without cancelling the thermal history) as follows by usingthe Differential Scanning calorimetry (D.S.C.) on a Perkin Elmer DSC-7instrument. A weighed sample (5-10 mg) obtained from the polymerization(or a weighed sample of the hot melt adhesive composition) was sealedinto aluminium pans and heated at 200° C. with a scanning speedcorresponding to 10° C./minute. The sample was kept at 200° C. for 5minutes, thereby allowing complete melting of the crystallites. Thesample was then stored for 10 days at room temperature. After 10 days,the sample was subjected to DSC, the sample was cooled to −20° C., andthen the sample was heated at 200° C. with a scanning speedcorresponding to 10° C./min. In this heating run, the peak temperature(or temperatures when more than one peak was present) were recorded asthe melting temperatures (TmI), and the area under the peak (or peaks)as global melting enthalpy after 10 days (DH TmI).

Glass transition temperature (Tg) via Dynamic Mechanical ThermalAnalysis (DMTA). Molded specimens of 76 mm by 13 mm by 1 mm were fixedto the DMTA machine for tensile stress. The frequency of the tension andrelies of the sample was fixed at 1 Hz. The DMTA translates the elasticresponse of the specimen starting from −100° C. to 130° C. The elasticresponse was plotted versus temperature. The elastic modulus for aviscoelastic material was defined as E=E′+iE″. In some instances, theDMTA split the two components E′ and E″ by resonance and plotted E′ vstemperature and E/E″=tan (δ) vs temperature. The glass transitiontemperature Tg was assumed to be the temperature at the maximum of thecurve E/E″=tan (δ) vs temperature.

Rotational (Brookfield) Viscosity

for the polymer: measured at 180° C. and a deformation rate of and 100s⁻¹, using a Rheolab QC instrument, which is a rotational rheometer,including a high-precision encoder and a dynamic EC motor. In someinstances, the controlled shear rate (CR) or the controlled shear stress(CS) test settings were selected. During the test, the sample wassubjected at a deformation rate sweep from 1 s⁻¹ to 1000 s⁻¹. The torquewas measured for each deformation rate and the corresponding viscositywas calculated by the instrument software;for the hot melt adhesive composition: determined using a Bohlin Geminiviscometer (Malvern) and the following operative conditions: cone/plate1°/20 mm; gap 30 micron; temperature range: 110°−190° C.; shear rate 100s⁻¹.

Crystallinity was measured by X-Ray diffraction according to thefollowing method: The instrument used to measure crystallinity was anX-ray Diffraction Powder Diffractometer (XDPD) that used the Cu-Kα1radiation with fixed slits and collected spectra between diffractionangle 2Θ=5° and 2Θ=35° with step of 0.1° per 6 seconds.

The samples were diskettes of about 1.5-2.5 mm of thickness and 2.5-4.0cm of diameter made by compression molding. The diskettes were aged at23° C. for 96 hours.The specimen was inserted in the XDPD sample holder. The XRPD instrumentwas set to collect the XRPD spectrum of the sample from diffractionangle 2Θ=5° to 2Θ=35° with step of 0.1° by using counting time of 6seconds. At the end, the final spectrum was collected.Ta was defined as the total area between the spectrum profile and thebaseline expressed in counts/sec·2Θ. Aa was defined as the totalamorphous area expressed in counts/sec·2Θ. Ca was total crystalline areaexpressed in counts/sec·2Θ.The spectrum or diffraction pattern was analyzed in the following steps:1) a linear baseline was defined for the whole spectrum and the totalarea (Ta) was calculated between the spectrum profile and the baseline;2) an amorphous profile was defined along the whole spectrum, thatseparated the amorphous regions from the crystalline regions accordingto the two phase model;3) the amorphous area (Aa) was calculated as the area between theamorphous profile and the baseline;4) the crystalline area (Ca) was calculated as the area between thespectrum profile and the amorphous profile as Ca=Ta−Aa; and5) the degree of crystallinity of the sample was calculated using thefollowing formula:

% Cr=100×Ca/Ta

Intrinsic viscosity: determined in tetrahydronaphthalene at 135° C.according to ASTM D 2857.

Density: Determined according to ISO 1183-1, method A, Part 1: immersionmethod. Test specimens were obtained by compression molded plaques.Density was measured after 10 days conditioning.

Fractions soluble and insoluble in xylene at 0° C.: 2.5 g of polymercomposition and 250 cm³ of o-xylene were introduced to a glass flaskequipped with a refrigerator and a magnetic stirrer. The temperature wasraised in 30 minutes up to the boiling point of the solvent. Theresulting clear solution was then kept under reflux and stirring forfurther 30 minutes. The closed flask was then cooled to 100° C. in airfor 10 to 15 minutes under stirring and then kept for 30 minutes inthermostatic water bath at 0° C. for 60 minutes. The resulting solid wasfiltered on quick filtering paper at 0° C. 100 cm³ of the filteredliquid was poured in a pre-weighed aluminum container which was heatedon a heating plate under nitrogen flow, to remove the solvent byevaporation. The fraction (percent by weight) of polymer soluble inxylene (XS) was calculated from the average weight of the residues. Thepolymer fraction insoluble in o-xylene at 0° C. (XI) was calculated as:XI (%)=100−XS (%).

Yellowness index measured according to ASTM method D1925.

Flexural modulus was measured according to ISO 178. Specimens forflexural test were cut from compression molded plaques pressed at 200°C. and aged via autoclave at room temperature for 10 min at 2 kbar.Specimens thickness was of 4 mm.

Preparation of catalyst components:Dimethylsilyl{(2,4,7-trimethyl-1-indenyl)-7-(2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene)}zirconium dichloride (metallocene A-1) was prepared as described inExample 32 of Patent Cooperation Treaty Publication No. WO01/47939.

Preparation of the hot melt adhesive compositions: the butene-1copolymers (PB-1), or commercial polymers of the comparative examples,and the resin were melted in a ventilated oven at 170° C. andsubsequently mixed in a high speed mixer (Thinky) at 1200 rpm. Themixing process was carried out in 2/3 steps:

step 1: about half of the amount of butene-1 copolymer, about half theamount of the resin and the whole amount of additive were loaded to themixer and mixed for 8 minutes;step 2: the rest of the polymer and the resin were loaded to the mixerand mixed for 8 minutes; and optionallystep 3: the composition was left to stand for 10 minutes andsubsequently the wax was added.The resulting blend was mixed for 8 minutes.

After complete mixing, the blend was poured onto a silicone-coatedrelease paper, and an adhesive film of 300 μm was produced with a rollerpress.

Overlap Shear Strength (OLS). The overlap shear strength of the hot meltadhesive compositions was determined by adhering 300±50 mm2 ofoverlapping ends of specimens of different materials measuring 25×75×1.5mm with a layer of the hot melt adhesive composition to be tested, suchthat the free ends of the specimens extend in opposite directions. Thespecimens were pressed together with 800 kPa=80N/cm² pressure for 30seconds. The samples were tested after 24 h storage at room temperature(25°±2° C.). The free ends of the specimens were inserted in the jaws ofa Zwick Roll Universal test system Type UTS 20 kN table moduleconstructed to DIN EN 51220, Zwick GmbH & Co. KG 89079 Ulm. Load celltype U2A, 20 kN, Hottinger Baldwin Messtechnik, 64293 Darmstadt. Thespecimens were separated with an angle of 180°, pulling the jaws at arate of 2 mm/min. The overlap shear strength value was recorded inMegaPascals (MPa). The following conditioned materials were used:

aluminum alloy AlMg3 sand blasted with high-class corundum F100;cleaning standard SA ½ according to ISO 8501-1;polypropylene (PP) cleaned with methyl ethyl ketone, 5 minutes dryingtime;wood (beech): dust removed with compressed air, surface roughening withabrasive paper (80 grain size), dust removed with compressed air afterabrasion.

Shear Adhesion Failure Temperature. Measured according to the testmethod PSTC-17 (Date of issuance 12/12).

Open time. As used herein, the “open time” was defined as the longesttime that an adhesive material remains capable of adhesion after theadhesive material has been cooled from the melt to room temperature. Auniform bead of 1.5 g/m of the hot melt adhesive composition molten at170° C. was applied onto a specimen of cardboard substrate 200×24.8 mmat ambient temperature (one side coated, 400 g/m² chromo duplexcardboard GD2), and then the second cardboard specimen pressed on to thebed of hot melt adhesive composition by a 2 kg roller. After fixedintervals of 5 seconds, the second cardboard specimen was slowly pulledapart. The total time until no fiber tear occurred was recorded as theopen time for the adhesive for that sample specimen. An average of theopen time was taken from three such recordings. The relative open timeis expressed as % with respect to the lowest value.

Example 1

Preparation of the catalytic solution: Under nitrogen atmosphere, 6400 gof a 33 g/L solution of triisobutylaluminum (TIBA) in isododecane and567 g of 30% wt/wt solution of methylalumoxane (MAO) in toluene wereloaded in a 20 L jacketed glass reactor, stirred by an anchor stirrer,and allowed to react at room temperature for about 1 hour understirring.

After this time, 1.27 g of metallocene A-1 was added and dissolved understirring for about 30 minutes.

The final solution was discharged from the reactor into a cylinderthrough a filter to remove eventual solid residues.

The composition of the solution resulted to be:

metallocene Al Zr Al/Zr conc. (wt. %) (wt. %) (mol ratio) (mg/l) 1.720.0029 2001 137

Polymerization of the butene-1 copolymer. The polymerization was carriedout in two stirred reactors operated in series, wherein liquid butene-1constituted the liquid medium. The catalyst system was fed in bothreactors. The polymerization conditions are reported in Table 1. Thebutene-1 copolymer was recovered as melt from the solution and cut inpellets. The copolymer was further characterized, and the data arereported in Table 2.

Example 2

Preparation of the catalytic solution: Under nitrogen atmosphere, 6400 gof a 33 g/L solution of TIBA in isododecane and 567 g of 30% wt/wtsolution of MAO in toluene were loaded in a 20 L jacketed glass reactor,stirred by an anchor stirrer, and allowed to react at room temperaturefor about 1 hour under stirring.

After this time, 1.27 g of metallocene A-1 was added and dissolved understirring for about 30 minutes.

The final solution was discharged from the reactor into a cylinderthrough a filter to remove eventual solid residues.

The composition of the solution resulted to be:

metallocene Al Zr Al/Zr conc. (wt. %) (wt. %) (mol ratio) (mg/l) 1.720.0029 2001 137

Polymerization of the butene-1 copolymer. The polymerization was carriedout in two stirred reactors operated in series, wherein liquid butene-1constituted the liquid medium. The catalyst system was fed in bothreactors. The polymerization conditions are reported in Table 1. Thebutene-1 copolymer was recovered as melt from the solution and cut inpellets. The copolymer was further characterized, and the data arereported in Table 2.

TABLE 1 Example 1 Example 2 First reactor Temperature ° C. 75 75 H2 inliquid phase molar ppm 2600 3248 C2 in liquid phase wt. % — 0.3 MileageKg/gMe 1953 1485 Split wt.% 22 60 C2 content (A1) wt. % 0 1 C2 content(A1) mole % — 1.98 Second reactor Temperature ° C. 75 75 H2 in liquidphase molar ppm 2600 3248 C2 in liquid phase wt. % 4.3 0.4 Split wt. %78 40 C2 content (A1) wt. % 6.8 1 C2 content (A1) mole % 12.7 1.98 Totalmileage Kg/gMe 1722 1539 Total C2 content wt. % 5.3 1.0 Total C2 contentmole % 10.07 1.98 Note: kg/gMe = kilograms of polymer per gram ofmetallocene A-1; Split = amount of polymer produced in the concernedreactor.

TABLE 2 Example 1 Example 2 MFR (190° C./2.16 Kg) g/10 min. 610 1200Intrinsic viscosity (IV) dl/g 0.5 0.4 Mw/Mn 2.2 2.1 TmII ° C. 98.1 81.9TmI ° C. 96.0 103 Tg ° C. −26 −13 Viscosity (180° C.) mPa · s 18,00010,000 Crystallinity % 26 58 Density g/cm³ 0.8900 0.9090 FlexuralModulus MPa 100 350

Example 3-4 and Comparative Examples 5-6

Hot melt adhesive compositions were prepared with the formulationindicated in Table 3. The hot melt adhesive compositions were tested forthermal properties, which are reported in Table 3.

TABLE 3 Example Example Comp. Comp. 3 4 ex. 5 ex. 6 Evatane 28-420 wt. %30.0 Affinity GA 1900 wt. % 34.7 PB-1 (Example 1) wt. % 34.7 PB-1(Example 2) wt. % 34.7 Eastotac H130L wt. % 45.0 45.0 49.7 45.0 SasolWax H1 wt. % 20.0 20.0 20.0 20.0 AO-1010 wt. % 0.3 0.3 0.3 0.3 TmI ° C.102 99 104 85 Tc ° C. 94 93 93 93 Tg ° C. −22 −22 (*) (*) (*) = notdetectable

Evatane™ 28-420 was an EVA copolymer with a vinyl acetate content of 28wt. %. commercially available from Arkema.

Affinity™ GA 1900 was a polyolefin elastomer, commercially availablefrom Dow Chemicals.

Eastotac™ H-130L was a hydrogenated hydrocarbon resin, having a ring andball softening point of 130° C., commercially available from EastmanChemical Company.

Sasol Wax H1 was a Fischer-Tropsch wax, commercially available fromSasol.

Irganox™ 1010 was a sterically hindered phenolic antioxidant.

The composition of Examples 3 and 4 showed thermal stability after 48 hstorage in a ventilated oven at 180° C. in open glass beakers. Thecomposition of Examples 3 and 4 showed no gel formation or skinning andcolor retention compared to Comparative Examples 5 and 6.

FIG. 1 shows the viscosity values of the hot melt adhesive compositionsrecorded at different temperatures.

Examples 7-8 and Comparative Examples 9-10

Hot melt adhesive compositions were prepared with the formulationindicated in Table 4. The hot melt adhesive compositions were tested forthermal properties, which are reported in Table 4.

TABLE 4 Example Example Comp. Comp. 7 8 ex. 9 ex. 10 Vestoplast 608 wt.% 28 Vestoplast 703 wt. % 41.5 Vestoplast 708 wt. % 28 Vestoplast 750wt. % 41.5 PB-1 (Example 1) wt. % 69.5 PB-1 (Example 2) wt. % 69.5Eastotac H130L wt. % 30.0 30.0 30 30 AO-1010 wt. % 0.5 0.5 0.5 0.5 TmI °C. 85 100 38 42 Tc ° C. / / 56 41 Tg ° C. −27 −26 −21 −17

Vestoplast 608, Vestoplast 703, Vestoplast 708 and Vestoplast 750 wereamorphous alpha-olefin polymers having Ring and Ball softening point,measured according to DIN EN 1427, of 157° C., 124° C., 106° C. and 107°C. respectively, commercially available from Evonik.

After first melting, the compositions of Examples 7 and 8 did not showany crystallization peak during cooling.

The compositions of Examples 7 and 8 showed thermal stability after 48 hstorage in a ventilated oven at 180° C. in open glass beakers. Thecompositions of Examples 7 and 8 showed no gel formation or and lesscolor change was observed compared to the Comparative Examples 9 and 10.

FIG. 2 shows the viscosity values of the hot melt adhesive compositionsrecorded at different temperatures.

FIG. 3 shows Overlap Shear Strength values on different substrates.

The absolute and relative open time and the SAFT value of the hot meltcomposition of Examples 7 and 8 and Comparative Example 9 are reportedin Table 5.

TABLE 5 Example Example Comp. 7 8 ex. 9 Open time sec. 290 293 243Relative open time % 119 121 100 SAFT ° C. 69 77 64

What is claimed is:
 1. A hot melt adhesive composition comprising: (A)28-75 wt. % of a copolymer of butene-1 with at least one comonomerselected from the group consisting of ethylene, propylene, C5-C10alpha-olefins and mixtures thereof, having copolymerized comonomercontent of 0.5-5.0 wt. % and Melt Flow Rate (MFR) values measuredaccording to ISO 1133 (190° C., 2.16 kg) from 200 to 1500 g/10 min.; and(B) 25-72 wt. % of at least one additional component selected from thegroup consisting of waxes, resins, plasticizers, additional polymers andmixtures thereof, wherein the amounts of A) and B) are referred to thetotal weight of A)+B).
 2. The hot melt adhesive composition according toclaim 1, wherein the butene-1 copolymer component (A) has a melt flowrate MFR measured according to ISO 1133 (190° C., 2.16 kg) from 400 toless than 1500 g/10 min.
 3. The hot melt adhesive composition accordingto claim 1, wherein the at least one comonomer is selected from thegroup consisting of ethylene, propylene, hexene-1, octene-1 and mixturethereof.
 4. The hot melt adhesive composition according to claim 1,wherein the butene-1 copolymer component (A) has a copolymerizedcomonomer content of 0.5-3.0 wt. %.
 5. The hot melt adhesive compositionaccording to claim 1, wherein the butene-1 copolymer (A) comprises abutene-1 copolymer composition comprising: (A1) a butene-1 homopolymeror a copolymer of butene-1 with at least one comonomer selected from thegroup consisting of ethylene, propylene, C5-C10 alpha-olefins andmixtures thereof, having a copolymerized comonomer content (CA1) of upto 3 wt. %; (A2) a copolymer of butene-1 with at least one comonomerselected from the group consisting of ethylene, propylene, C5-C10alpha-olefins and mixtures thereof, having a copolymerized comonomercontent (CA2) of 3-10 wt. %; wherein the butene-1 copolymer compositionhaving a total copolymerized comonomer content of 0.5-5.0 wt. % referredto the sum of (A1)+(A2).
 6. The hot melt adhesive composition accordingto claim 1, wherein the butene-1 copolymer component (A) has at leastone of the following additional features: (a) a molecular weightdistribution (Mw/Mn) lower than 4, the lower limit being 1.5; and/or (b)a melting point (TmII) lower than 110° C.; and/or (c) a melting point(TmII) higher than 80° C.; and/or (d) a glass transition temperature(Tg) in the range from −40° C. to −10° C.; and/or (e) a rotational(Brookfield) viscosity at 180° C. (shear rate 100 s−1) of from 5,000 to50,000 mPa·sec; and/or an X-ray crystallinity in the range 25-60%. 7.The hot melt adhesive composition according to claim 1, wherein the hotmelt adhesive composition comprises a composition (i) comprising: (A)30-40 wt. % of a copolymer of butene-1; (B.1) 15-25 w. % of at least onewax, (B.2) 42-52 wt. % of at least one resin; wherein the amounts of(A), (B.1) and (B.2) are referred to the total weight of(A)+(B.1)+(B.2).
 8. The hot melt adhesive composition according to claim7, wherein composition (i) has a rotational (Brookfield) viscosity at180° C. (shear rate 100 s−1) of lower than 7,000 mPa·s, the lower limitbeing 1,000 mPa·s.
 9. The hot melt adhesive composition according toclaim 1, wherein the hot melt adhesive composition comprises acomposition (ii) comprising: (A) 65-75 wt. % of a copolymer of butene-1;and (B.2) 25-35 wt. % of at least one resin, wherein the amounts of (A)and (B.2) are referred to the total weight of (A)+(B.2).
 10. The hotmelt adhesive composition of claim 9, wherein composition (ii) has arotational (Brookfield) viscosity at 180° C. (shear rate 100 s−1) of5,000-25,000 mPa·s.
 11. (canceled)
 12. (canceled)
 13. (canceled)
 14. Aprocess for preparing an article of manufacture comprising the step of:applying a hot melt adhesive composition to a substrate and anadditional step selected from the group consisting of woodworking,packaging and assembling, wherein the hot melt adhesive composition isselected from the group consisting of (a0) (A) 28-75 wt. % of acopolymer of butene-1 with at least one comonomer selected from thegroup consisting of ethylene, propylene, C5-C10 alpha-olefins andmixtures thereof, having copolymerized comonomer content of 0.5-5.0 wt.% and Melt Flow Rate (MFR) values measured according to ISO 1133 (190°C., 2.16 kg) from 200 to 1500 g/10 min.; and (B) 25-72 wt. % of at leastone additional component selected from the group consisting of waxes,resins, plasticizers, additional polymers and mixtures thereof, whereinthe amounts of A) and B) are referred to the total weight of A)+B); (ai)(A) 30-40 wt. % of a copolymer of butene-1; (B.1) 15-25 w. % of at leastone wax, (B.2) 42-52 wt. % of at least one resin; wherein the amounts of(A), (B.1) and (B.2) are referred to the total weight of(A)+(B.1)+(B.2); and (aii) (A) 65-75 wt. % of a copolymer of butene-1;and (B.2) 25-35 wt. % of at least one resin, wherein the amounts of (A)and (B.2) are referred to the total weight of (A)+(B.2).
 15. The processfor preparing an article of manufacture to claim 14, wherein theadditional step is packaging and the hot melt adhesive composition iscomposition (ai).
 16. The process for preparing an article ofmanufacture to claim 14, wherein the additional step is selected fromthe group consisting of woodworking and assembling and the hot meltadhesive composition is composition (aii).